Chapter 12
Skin: Integumentary System
Related Combining Forms
Structure
Related Combining Forms
Skin
cutane/o, dermat/o, derm/o
Sebaceous glands
seb/o
Sweat glands
hidr/o
Hair
pil/i, pil/o
Nails
onych/o, ungu/o
Integumentary System
• Consists of skin and its related structures (sebaceous glands, sweat glands, hair, and nails) • Average adult has two square yards of skin, making it the largest body organ
Functions of Skin
• Keeps the body waterproof, hence preventing fluid loss • When intact, skin blocks the entrance of pathogens • Contains receptors for the sense of touch • Synthesizes vitamin D from the sun
Functions of Related Structures
• Sebaceous glands – Secrete sebum that lubricates skin and discourages growth of bacteria on skin
• Sweat glands – Assist with body water content and temperature regulation – Excretion of small amounts of metabolic wastes
Functions of Related Structures
• Hair – Helps control the loss of body heat
• Nails – Protect dorsal surface of last bone of each toe and finger
Structures of Skin and Its Related Structures
• Skin – Specialized tissues – Three layers • Epidermis • Dermis • Subcutaneous – (cutane: skin; -ous: pertaining to)
Structures of Skin and Its Related Structures
Epidermis
– (epi-: above or upon; derm: skin; -is: noun ending)
• Outermost layer of skin • Made of specialized epithelial tissues • Contains no blood vessels or connective tissue • Depends on the lower layers for nourishment
Epidermis
• Epithelial tissues – Form protective covering for internal and external surfaces of the body
• Squamous epithelial tissue – Forms upper layer of epidermis – Flat, scaly cells continuously shed
Epidermis
• Basal layer – Lowest layer of epidermis – Site of new cell production – When cells reach surface, they die and become filled with keratin
• Keratin – Fibrous, water-repellent protein • Soft keratin: component of epidermis • Hard keratin: found in hair and nails
Epidermis
• Melanocytes – Special cells in basal cell layer – Produce and contain dark brown to black pigment known as melanin
• Melanin – Pigment that determines color of skin, produces freckles and age spots – Protects skin from some of the harmful UV rays
Dermis
• Directly below epidermis • Contains connective tissue, blood and lymph vessels, nerve fibers, hair follicles, sebaceous glands, and sweat glands • Sensory nerve endings – Sensory receptors for touch, temperature, pain, and pressure
Tissues Within Dermis
• Collagen – Tough flexible fibrous protein found in skin, bones, cartilage, tendons, and ligaments
• Mast cells – Found in connective tissue of dermis – Respond to injury, infection, or allergy by producing and releasing heparin (anticoagulant) and histamine (causes allergic response)
Subcutaneous Layer
• Located below the layers of skin • Connects skin to the surface muscles • Made of loose connective tissue and adipose tissue • Lipocytes manufacture and store large quantities of fat – (lip/o: fat; -cytes: cells)
Sebaceous Glands
• Located in dermis • Closely associated with hair follicles • Sebum – Oily substance released through ducts opening into hair follicles – Lubricates skin – Acidic, thus discourages growth of bacteria on skin
Sebaceous Glands
• Mammary glands – Produce milk – Also part of the reproductive system
Sweat Glands
• Sudoriferous glands • Located on almost all body surfaces • Two types – Apocrine • Found at hair follicles
– Eccrine • Open onto skin • Most numerous in palms, soles, and forehead
Sweat Glands
• Pores – Opening on the surface of skin – Act as ducts of the sweat glands
• Perspiration – Secreted by sweat glands – 99% water plus salt and metabolic waste – Evaporation of sweat cools the body
Sweat Glands
• Hidrosis – Production and excretion of perspiration
Hair
• Composed of dead protein cells filled with hard keratin • Color of hair determined by melanin • Hair follicles – Sacs holding the root of hair fibers
• Arrector pili – Muscle fibers attached to hair follicles that cause hair to stand erect, reducing heat loss
Nails
• Unguis (fingernail or toenail) • Keratin plate protecting dorsal surface of the last bone of each finger and toe • Nail body – Translucent – Molded to surface of underlying tissues – Make of hard, keratinized plates of epidermal cells
Nails
Nails
• Nail bed – Joins nail body to underlying connective tissue – Nourishes the nail – Blood vessels provide pink color
• Free edge – Portion of nail not attached to the nail bed – Extends beyond tip of the finger or toe
Nails
• Lunula – Half-moon-shaped region at nail root – Site of new keratin cell formation • (lun: moon; -ula: little)
• Cuticle – Epidermis attached to the surface of nail
• Nail root – Fastens nail to finger/toe
Medical Specialties Related to Integumentary System
• Dermatologist – Specializes in diagnosing/treating disorders of the skin • (dermat: skin; -ologist: specialist)
• Plastic surgeon – Specializes in surgical restoration or reconstruction of body structures • (-plasty: surgical repair)
Medical Specialties Related to Integumentary System
• Cosmetic surgeon – Plastic surgeon who performs operations for aesthetic rather than medical reasons
Pathology of Integumentary System
• Sebaceous Glands – Acne vulgaris • Chronic inflammatory disease caused by the overproduction of sebum around the hair shaft
– Comedo • Noninfected lesion composed of sebum and keratin in hair follicle • Closed comedo: whitehead • Open comedo: blackhead
Sebaceous Glands
– Epidermoid cyst • Closed sac just under the skin • Contains fatty material
– Seborrhea • Overproduction of sebum • (seb/o: sebum; -rrhea: flow or discharge)
Sebaceous Glands
– Seborrheic dermatitis • Inflammation causing scaling/itching of upper layers of skin/scalp
– Seborrheic keratosis • Benign skin growth having a waxy appearance • Varied colors • Common in elderly
Sweat Glands
– Anhidrosis • Condition of lacking sweat in response to heat – (an-: without; hidr: sweat; -osis: abnormal condition)
– Diaphoresis • Profuse sweating – (dia-: through or complete; phor: movement; -esis: abnormal condition)
– Heat rash • Itchy rash related to the blockage of sweat glands by bacteria and dead cells
Sweat Glands
– Hyperhidrosis • Excessive sweating in one area or over the whole body – (hyper-: excessive; hidr: sweat; -osis: abnormal condition)
– Sleep hyperhidrosis • Hyperhidrosis during sleep
Hair
– Folliculitis • Inflammation of hair follicles – (follicul: hair follicle; -itis: inflammation)
– Trichomycosis axillaris • Superficial bacterial infection of hair shafts in areas with extensive sweat glands, such as armpits – (trich/o: hair; myc: fungus; -osis: abnormal condition; axill: armpit; -ary: pertaining to)
Excessive Hairiness
– Hirsutism • Excessive body and facial hair in women, usually occurring in a male pattern – (hirsut: hairy; -ism: condition)
Abnormal Hair Loss
– Alopecia • Partial or complete loss of hair – (alopec: baldness; -ia: condition)
– Alopecia areata • Autoimmune disorder attacking hair follicles • Occurs in patches on scalp or elsewhere on body
Abnormal Hair Loss
– Alopecia totalis • Loss of all hair on the scalp
– Alopecia universalis • Total loss of hair on all parts of the body
– Androgenic alopecia • Hair loss due to hormonal changes • Occurs in males and females
Nails
– Clubbing • • • •
Abnormal curving of nails Often accompanied by enlargement of fingertips May be hereditary May be due to changes associated with oxygen deficiencies related to coronary or pulmonary disease
Nails
– Koilonychia • Outer surface of nail is concave • Often indicates iron-deficiency anemia – (koil: hollow or concave; onych: fingernail or toenail; -ia: condition)
– Onychia • Inflammation of matrix of nail • May result in the loss of nail
Nails
– Onychocryptosis • Edges of toenail curve inward and cut into the skin – (onych/o: fingernail or toenail; crypt: hidden; -osis: abnormal condition)
– Onychomycosis • Fungal infection of nail – (myc: fungus)
– Paronychia • Infection of skin fold around a nail – (par-: near)
Skin Pigmentation
• Acanthosis nigricans – Development of dark wart-like patches on one or more areas of skin
• Age spots – Discoloration caused by sun exposure
• Albinism – Genetic condition characterized by lack of pigment in skin, hair, and irises of eyes • (albin: white)
Skin Pigmentation
• Chloasma – Brownish spots on face – May occur during pregnancy, and disappear after delivery of infant
• Vitiligo – Irregular patches of white skin related to destruction of melanocytes
Bleeding into Skin
• Contusion – Injury to underlying tissues without breaking the skin – Discoloration caused by accumulation of blood within the skin • (contus: bruise; -ion: condition)
Bleeding into Skin
• Ecchymosis – Large, irregular purplish discoloration due to bleeding under the skin • (ecchym: pouring out of juice; -osis: abnormal condition)
• Purpura – Multiple purple discoloration on skin due to bleeding underneath the skin • (purpur: purple; -a: noun ending)
Bleeding into Skin
Bleeding into Skin
• Petechiae – Small, pinpoint hemorrhages less than 2 mm in diameter
• Hematoma – Usually due to injury – Swelling of clotted blood trapped in tissues – Blood is reabsorbed • (hemat: blood; -oma: tumor)
Surface Lesions
• Crust – Collection of dried serum and cellular debris
• Erosion – Wearing away of a surface
• Macule – Flat, discolored spot less than 1 cm in diameter
Surface Lesions
Surface Lesions
• Nodule – Solid, raised skin lesion larger than 0.5 cm in diameter
• Papule – Raised, red lesion less than 0.5 cm in diameter – Does not contain pus
Surface Lesions
• Plaque – Scaly, solid raised area of closely spaced papules
• Scales – Flakes or dry patches of excess dead epidermal cells – Some shedding is normal – Excessive shedding associated with the skin disorders
Surface Lesions
• Verrucae – Small, hard skin lesions caused by human papillomavirus – Also known as warts
• Wheal – Small, itchy bump – May be due to an allergic reaction
Fluid-Filled Lesions
• Abscess – Closed pocket containing pus – Due to bacterial infection
• Purulent – Producing or containing pus
• Exudate – Fluid leaking out of an infected wound
Fluid-Filled Lesions
• Cyst – Abnormal sac containing fluid, or semisolid material
• Pustule – Small, circumscribed lesion containing pus – Contained within a limited area
Fluid-Filled Lesions
Fluid-Filled Lesions
• Vesicle – Blister, less than 0.5 cm in diameter – Contains watery fluid
• Bulla – Large blister more than 0.5 cm in diameter
Lesions Through Skin
• Abrasion – Superficial layers are scraped away
• Fissure – Crack-like break in the skin
• Laceration – Torn or jagged wound
Lesions Through Skin
Lesions Through Skin
• Pressure sore – Open ulcerated wound caused by the prolonged pressure on an area of the skin
• Needlestick injury – Accidental puncture wound caused by hypodermic needle
• Ulcer – Open lesion resulting in tissue loss around the edges
Birthmarks
• Pigmented birthmarks – Also known as moles or café-au-lait spots
• Vascular birthmarks – Caused by blood vessels close to the skin's surface
Birthmarks
• Capillary hemangioma – Soft, raised, pink or red vascular birthmark – Benign tissue mass • (hem: blood; angi: blood or lymph vessels; -oma: tumor)
• Port-wine stain – Flat vascular birthmark made up of dilated blood capillaries – Creates reddish-purple discoloration
Dermatitis
• Inflammation of the skin • Contact dermatitis – Localized allergic response • (dermat: skin; -itis: inflammation)
• Eczema – Recurring dermatitis characterized by redness, itching, and dryness
Dermatitis
• Exfoliative dermatitis – Widespread scaling of the skin
• Pruritus – Itching associated with the most forms of dermatitis • (prurit: itching)
Erythema
• Redness of skin due to capillary dilation – (erythem: flushed; -a: noun ending)
• Erythema infectiosum – Mildly contagious viral infection common in children – Also known as fifth disease
Erythema
• Erythema multiforme – Generalized allergic reaction to illness, infection, or medication
• Erythema pernio – Purple-red inflammation occurring when small blood vessels below the skin are damaged
Erythema
• Erythroderma – Abnormal redness of entire skin surface • (erythr/o: red; -derma: skin)
• Exanthem – Widespread rash
• Hand, foot, and mouth disease – Mild viral infection common in children under 5 years of age – Sores in mouth/throat; rash on hands/feet
General Skin Conditions
• Dermatosis – Denotes skin lesion or eruption of any type not associated with inflammation
• Ichthyosis – Hereditary disorders characterized by dry, thickened, scaly skin • (ichthy: dry or scaly; -osis: abnormal condition)
General Skin Conditions
• Lipedema – Characterized by accumulation of fat and fluid in tissues under the skin of hips and legs • (lip: fat; -edema: swelling)
• Systemic lupus erythematosus – Autoimmune disorder characterized by red, scaly rash on face/upper trunk
• Psoriasis – Occurrence of red papules with silvery scales
General Skin Conditions
• Roseacea – Tiny red pimples and broken blood vessels – Commonly seen in adults 30–60 years of age
• Rhinophyma – Hyperplasia of tissues of nose – Usually seen in older men • (rhin/o: nose; -phyma: growth)
General Skin Conditions
• Scleroderma – Autoimmune disorder in which connective tissues become thickened and hardened • (scler/o: hard; -derma: skin)
• Urticaria – Itchy wheals due to allergic reaction • (urtic: rash; -aria: connected with)
General Skin Conditions
• Xeroderma – Excessively dry skin • (xer/o: dry; -derma: skin)
Bacterial Skin Infections
• Carbuncle – Cluster of furuncles
• Cellulitis – Acute bacterial infection within connective tissues – Characterized by malaise, swelling, warmth, and red streaks
Bacterial Skin Infections
• Furuncles – Large, tender, swollen areas caused by staphylococcal infection around hair follicles or sebaceous glands
• Gangrene – Death of tissue, followed by bacterial invasion, which may also enter bloodstream – Commonly due to the loss of circulation to the affected tissues
Bacterial Skin Infections
• Impetigo – Highly contagious bacterial skin infection – Common in children
• Necrotizing fasciitis – Caused by Group A strep that enters the body through a skin wound
Bacterial Skin Infections
• Pyoderma – Acute, pus-forming bacterial skin infection • (py/o: pus; -derma: skin)
Fungal Skin Infections
• Mycosis – Abnormal condition caused by fungus • (myc: fungus; -osis: abnormal condition)
• Tinea – Fungal infection on skin, hair, or nails – Known as ringworm
Parasitic Skin Infestations
• Pediculosis – Infestation with lice • (pedicul: lice; -osis: abnormal condition)
• Scabies – Skin infection caused by itch mites
Skin Growths
• Callus – Thickening of the part of the skin caused by repeated rubbing
• Cicatrix – Normal scar
• Granulation tissue – Forms during healing of a wound
Skin Growths
• Granuloma – Small swelling of granulation tissue – May result from inflammation, injury, infection • (granul: granular; -oma: tumor)
• Keloid – Thickened scar expanding beyond the boundaries of original incision • (kel: growth or tumor; -oid: resembling)
Skin Growths
• Keratosis – Overgrowth and thickening of the skin • (kerat: hard or horny)
• Lipoma – Benign fatty tumor located between the skin and muscle layer
• Nevus – Small, dark skin growth developing from melanocytes
Skin Growths
• Dysplastic nevi – Atypical moles – May develop into skin cancer
• Papilloma – Benign wart-like growth on epithelial tissue or elsewhere in the body • (papill: resembling a nipple; -oma: tumor)
Skin Growths
• Polyp – Mushroom-like growth from the surface of mucous membrane
• Skin tags – Flesh-colored polyps hanging from the body by fine stalks – Benign – Tend to enlarge with age
Skin Cancers
• Malignant growth on skin • Three types – Basal cell carcinoma – Squamous cell carcinoma – Melanoma
Skin Cancers
• Actinic keratosis – Precancerous skin growth occurring on sundamaged skin – Lack of treatment may lead to cancer
• Basal cell carcinoma – Malignant tumor of basal cell layer of epidermis – Rarely spreads
Skin Cancers
• Squamous cell carcinoma – Malignant tumor of squamous cells of epithelium – Can spread quickly to other body systems
• Malignant melanoma – Occurs in melanocytes – Initial symptoms are change in the size, shape, or color of a mole • (melan: black; -oma: tumor)
Burns
• Injury caused by heat, flame, electricity, sun, chemicals, or radiation • Severity described according to the percentage of the total body skin surface affected or by depth or layer of skin involved
Diagnostic Procedures of Integumentary System
• Biopsy – Removal of small piece of living tissue for confirmation of diagnosis • (bi: pertaining to life; -opsy: view of)
• Exfoliative cytology – Cells are scraped from tissue for microscopic examination
Treatment Procedures of Integumentary System
• Preventive measures – Sunscreen • Blocks harmful ultraviolet B (UVB) rays or ultraviolet A (UVA) rays • Measured in terms of strength of sun protection factor (SPF)
Burn Treatment
– Depends on degree of burn, and percentage of the body surface involved – Burn centers provide pain relief, debridement, dermoplasty, IV fluids and nutritional supplements, antibiotics, cosmetic reconstruction, and rehabilitation
Tissue Removal
– Cauterization • Destruction of tissue by burning
– Chemabrasion • Use of chemicals to remove outer layers of skin
– Cryosurgery • Destruction or elimination of abnormal tissue cells – (cry/o: cold; -surgery: operative procedure)
Tissue Removal
– Curettage • Removal of surface material by scraping
– Debridement • Removal of dirt, foreign objects, damaged tissue, and cellular debris from a wound • Prevention of infection and promotion of healing
– Irrigation and debridement • Pressurized fluid to clean wound debris
Tissue Removal
– Dermabrasion • Involves use of revolving wire brush or sandpaper
– Electrodesiccation • Destruction of tissue by the use of electric spark
– Incision • Use of surgical instrument to cut open a lesion
Tissue Removal
– Mohs' surgery • Layers of cancerous tissue are removed and examined under the microscope • Procedure is repeated until margin that is clear of all cancerous tissue is achieved
Laser and Light Source Treatments of Skin Conditions
• Laser (Light Amplification by Stimulated Emission of Radiation) – Laser tube filled with solid, liquid, or gas substance is stimulated to emit light at a specific wavelength
• Photosensitizing drug – Administered topically or by injection – After activation, drugs produce a form of oxygen that kills nearby cells
Medications for Treatment of Skin
• Retinoids – Derived from vitamin A and are used because of their effect on epithelial cell growth
• Topical steroids – Derivatives of natural corticosteroid hormones – Treatment of various skin disorders
Cosmetic Procedures
• Blepharoplasty – Surgical reduction of upper and lower eyelids by removing sagging skin • (blephar/o: eyelid; -plasty: surgical repair)
• Botox – Used to reduce moderate-to-severe frown lines, to treat migraines and muscle spasms
• Collagen replacement therapy – Used for soft-tissue augmentation
Cosmetic Procedures
• Dermatoplasty – Replacement of damaged skin of a patient with the healthy tissue taken from a donor site
• Electrolysis – Use of electric current to destroy hair follicles
• Lipectomy – Surgical removal of fat from beneath the skin to improve physical appearance
Cosmetic Procedures
• Liposuction – Surgical removal of fat beneath the skin with the aid of suction
• Rhytidectomy – Surgical removal of excess skin and fat from the face • (rhytid: wrinkle; -ectomy: surgical removal)
Cosmetic Procedures
• Sclerotherapy – Injection of a saline sclerosing solution for treatment of spider veins (nonessential veins seen through the skin)
